The following listing represents a survey and a short description of 'Earth Observing Mis­ sions' in alphabetical order. The listing in Part A considers completed-, operational-as well as planned missions on an international scale (Earth observations from space know no na­ tional boundaries). A look into past activities is important for reasons of heritage, context and of perspective. The document is intended for all who want to keep track of missions and sensors in the fast -growing field of Earth observations. There cannot be any claim to com­ pleteness, although a considerable effort was made to collect and integrate all known mis­ sions and sensors into this book.